1. Field of the Invention
The present invention relates to personal authentication systems and personal authentication methods and, more particularly, to a personal authentication system and a personal authentication method using the electrical resistance of the epidermis.
2. Description of the Related Art
In recent years, along with the popularization of the Internet, the applicable range of networks has been rapidly expanding and the value and amount of distributed information has been increasing year after year. This has been accompanied with an increase in illegal activity and crimes concerning a variety of electronic information that has raised social issues and the effects of the social issues tend to increase. Such illegal activity includes physical intrusion into computer facilities, illegal use of equipment, and illegal access from networks.
Countermeasures against such an illegal activity or crimes include, first, enhanced physical security for preventing illegal access to facilities and, second, enhanced information security for preventing illegal network intrusion or illegal access to information. Secure user identification provides effective means for both countermeasures. For example, the physical feature of a user is used to perform personal authentication.
As computer technologies and communication technologies progress more and more, electrical equipment used in ordinary life will have a CPU or a memory and will be operated with given instructions or stored data. Legal users are victims to illegal access to such equipment and illegal operation thereof. Secure identification of the users is effective means for preventing such illegal access and illegal operation.
Ultimate identification means is a biometrics authentication using physical features. Although fingerprints have been used for a long time in biometrics authentication, a personal authentication method using new biological information has been of interest in recent years. For example, it is hoped that an iris authentication technology using the pattern of the iris of a human eye that differs from person to person comes into wide use because of its high precision.
However, since fingerprints or irises are external biological features, high-precision reproduction is possible and thus undesirably permits an imposter to pose as an authenticated person. Since fingerprints or the like stay at places that are touched with a hand, they can be reproduced by current state-of-the-art technologies but the reproduced fingerprints or the like cannot be identified by common fingerprint identification systems.
Although methods that use internal biological information have been suggested as methods for overcoming the drawbacks of the existing authentication technologies described above, their size, cost, and limited applicable range cause problems, thus disadvantageously providing low practicability.